At present, main standard test blocks for calibration work of ultrasonic flaw detectors and probes mainly comprise V1 (IIW1) boat-shaped test blocks and V2 (IIW2) ox horn test blocks, which are mainly used for the detection of horizontal linearity, vertical linearity, dynamic range, sensitivity margin, differentiating force and blind areas, as well as incidence points, refraction angles and the like of the probes, and the detection surfaces of the probes are planes. Heel test blocks have the functions which are basically the same as those of the boast-shaped test blocks or the ox horn test blocks, but the detection surfaces of the probes are curved surfaces. The surfaces of workpieces are generally planes and curved surfaces, when the planes are used as the detection surfaces for performing flaw detection work, the boat-shaped test blocks and the ox horn test blocks are used for calibration of the instruments and the probes; and when the curved surfaces are used as the detection surfaces for performing the flaw detection work, there are no detection test blocks worldwide for the calibration of the instruments and the probes.
There have been no standard test blocks for debugging internationally for precision positioning of ultrasonic circumferential oblique defect detection of curved surface forged pieces. How to determine detection angle, scanning speed and zero point of each curved surface forged piece becomes an important difficult problem in the field of nondestructive detection. For the circumferential oblique defect detection of the parts of oil and gas drilling and production equipment, an internationally adopted flaw detection method is mainly as follows: a line is connected between peak values of a first reflex obtained on a notch between the inner diameter and the outer diameter to establish a datum line of vibration amplitude. But, the precision positioning of defects can not be ensued, and the existing contrast test blocks can not meet the calibration work of the angles, the speeds and the zero points.
Thus, a new contrast test block is needed to solve the above problems.